La ultrasonic welding of thermoplastic materials represents one of the most efficient and versatile technologies for joining plastic components in the industrial context. It is a process highly automatable using high-frequency sound waves to generate localised heat in the contact zone between the materials, causing them to melt without the use of adhesives, solvents or mechanical fixings. The result is a clean, fast and repeatable weldingideal for high volume production and critical applications.
Present for decades in the manufacturing industry, ultrasonic welding has evolved to meet the needs of more advanced sectors such as theautomotive, the electric mobilitythe medicalthe food and cosmetics packaging, the microelectronics, the filtration and the technical textile. Its reliabilitycombined with theenergy efficiency and the environmental sustainabilitymakes it a strategic technology for many Italian and European companies today.
The advantages of advanced technology such as ultrasonic welding are numerous:
The process is based on the transformation of theelectricity at high-frequency mechanical vibrations via a generator and a piezoelectric transducer. The vibrations, transmitted to the workpiece via a sonotrodeThey cause localised molecular friction in the contact zone, causing the thermoplastic materials to heat up and melt. The joint forms rapidly under pressure and solidifies in a strong and durable manner.
The main phases of the cycle include:
The main advantages of ultrasonic welding include:
Ultrasonic welders for thermoplastics vary depending on the application. The main parameters are:
With over 20 years of experience in ultrasonic technology, Sonomax Srl designs and implements:
Process certification and validation support.
Polypropylene, polyethylene, ABS, polycarbonate, PS, PA, bioplastics and many others
For reliable and repeatable welds, yes, but they are evaluated in the design phase.
Yes, if thermoplastic. We perform tests on PLA, PHA, PBS and bio blends.
Ultrasonic welding is one of the safest, most effective and fastest methods of joining thermoplastic materials.
The welding time is around milliseconds and it is possible to weld moulded parts and thermoplastic fabrics.
The ultrasonic technology allows the cutting and simultaneous closing of the synthetic fibres of fabrics, avoiding the typical fraying effect. During and after the cutting operation, the tool remains clean at all times, and the use of ultrasound is safe for operators as it does not burn and does not produce toxic fumes.
Ultrasonic stitching makes it possible to join two or more layers of fabric without adding adhesives, solvents or mechanical fixings. In addition, ultrasonic seams are hermetically sealed, preserving the contents of the product. One of the advantages is certainly related to energy, as the welding process has no negative impact.
Ultrasonic riveting is used to melt a peg, or pin, introduced into a hole. The plastic pin is brought into contact with the sonotrode, melting and forming a crimping head. This technique can also be used to fasten different materials or metal parts, such as car, motorhome and boat parts, or special electrical components (plugs, sockets, multi-sockets, connectors), or air filters and petrol/diesel filters.
This operation stems from the need to incorporate brass rivets into a thermoplastic material. The hole in the plastic melts under the action of ultrasound, allowing the rivet to be inserted. The rivet has a knurl, which increases the adhesion of the solder. Once the welded plastic has solidified, the rivet is perfectly incorporated.
In order to reduce the areas of friction between the parts, which make it difficult to initiate the melting process, it is advisable to create geometric protuberances on the parts themselves, known as energy directors, which allow the material to be melted over a relatively small area.
In order to choose the most suitable energy director geometry for your application, we list some examples below and in any case we are available to offer our experience and technical knowledge.
Common joints that incorporate the use of an energy director include: butt joints, segmented joints and tongue and groove joints.
Find out how to improve your production line with ultrasound
